Telephone-exchange system.



a. R. GORWIN. TELEPHONE EXCHANGE SYSTEM.

, APPLICATION FILED A1IG 10,1912. I 1,109,163.. Patented Sept. 1, 1914.

4 $HEETS-SHEET 1.

[NVENTURI I E-LMER RIIORWM ATTORNEY WRTNESSES E. R. 00min. TELEPHQNE.EXCHANGE SYSTEM.

APPLIGATION FILED AUG. 10. 1912.

Patented Sept. 1, 1914.

4 SHEETS-SHEET 2.

.1 INVENTOR E-TLMER R CORWIN AT TORNEY E. R, GORWIN.

' TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG. 10 1912. 1,109,163. v

#i-I I I I I III I III wrr'kns sss q- I INVENTOR I ELMER R.CRW1N ATTORNEY' Patented Sept. 1,1914.

4.SHEETSSEEET 3.

TELEPHONE BXGHANGE SYSTEM. APPLICATION FILED AUG. 10, 1912.

E. R. GORWIN.

Patented Sept. 1, 19M.

4 SHEETS-SHEET 4.

INVENTOR ELMELR R CORVV'IN ATTORNEY UNITED STATES PATENT OFFICE.

ELMER R. CORWIN, OF CHICAGO, ILLINOIS,' ASSIGNOR', BY MESNEASSIGNMEN'I'S TO FRANK B. COOK COMPANY, OF CHICAGO, ILLINOIS, ACORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent. Application filed August 10. 1912.Serial No. 714,416.

Patented Sept. 1, 1914.

To (IZZ whom, it may concern Be it known that I, ELMER R. Conwrx,citizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented a certain new and usefulImprovement in Telephone-Exchange Systems, of which the following is afull, clear, concise, and exact description, reference being had to theaccompanying drawings, forming a part of this specification.

My invention relates to those telephone exchange systems in whichelectro-magnetic mechanism is employed for extending telephone lines andwhile my invcntionhas been specifically embodied in a system in whichthe operators have control of such electro-magnetic mechanism yet theinvention is not to be restricted to such a system.

In accordance .With my invention I provide a telephone exchange systemwhich includes telephone lines, such for example as those which extendfrom subscribers stations to an exchange though the invention is not tobe limited to subscribers"telephone lines, extensions for such telephonelines, a line extending connecting device, controlling circuitsassociated with different telephone line extensions for governing theassociation of said connecting device, and operator controlled means forchanging the character of the controlling circuits.

My invention, in another of its aspects, may generally be described as atelephone system including telephone lines extending.

from stations to an exchange, extensions for such telephone lines havingcontacts at the exchange, a line extending connecting device forengagement with the contacts, controlling circuits for governing theassociation of said connecting device, each controlling circuit having acontact for engage ment with the connecting device, the controllingcircuits being associated with different telephone line extensions,means for changing the'character' of the controlling circuits associatedwith desired telephone line extensions, and means for maintaining theconnecting device in association with a modified controlling circuit.

In the preferred way of practising my invention each telephone line thatis to be extended is connected witha set of contacts which maybe in theform of traveling wipers, the waiting contacts of Whili are character.

divided into sets-each individual to a telephone line extension. Each ofthese sets of waiting contacts includes a contact that is contained in acontrolling circuit individual thereto.. Each of these controllingcircuits, as I have embodied my invention in one form. has a manuallycontrolled switching device individual thereto-for controlling its Thegroup of; wipers now individual to the line that is to be extendedrotates until one of the wipers of such group engages a contact of acontrolling circuit whose character has been temporarily modified forthe purpose of causing the arrest of the wipers, this particular waitingcontact and the wiper engaging the same establishing or otherwisemodifying the altered controlling circuit to arrest the wipers. Thewipers of the arrested group that are companion to the wiper engagingthe waiting contact of the altered controlling circuit themselves engagecontacts that are terminals of the selected talking extension. Thisparticular extension which has been added to a tele phone line mayextend directly to a subscribers station if the telephone system is of asufficiently small number of lines or it may extend to another group ofwipers which may be similarly connected with another telephone lineextension, and so on,

whereby the system may be adapted to any number of lines.

I will explain my invention more fully by reference to the accompanyingdrawings showing the preferred embodiment thereof and in which- Figure 1is a very simple diagram generally outlining important features of theinvention; Fig. 2 is a general diagrammatic view drawn along the linesof Fig. l but in whiclrtlie invention is adapted to a larger system;Fig. 3 is a diagram that is intended to be somewhat general but which ismore specific than the diagram of Fig 1; Figs. and 5, taken collectivelywith the conductors at the top margins thereof in alinement, illustrateone embodiment of the invention more in detail; and Fig. 6 shows adetail of construction.

Like parts are indicated by similar characters of reference throughoutthe different figures.

Referring first to Fig. 1, I have there illustrated telephone stations1, 2, 3 and A by meanscfci'rcles. Telephone station A is illus- -tionNo. 3.. The controlling circuits contain 55 tion with station No. 1. Theoperator will tratedas-havin its line manually extended by an operatory-means of a plu and ack at- .4,.the link-connector connecte with the pg '1: terminating in talking-wipers illustrated by the single wiper 5. Ihave shown the manual extension of the line-from sta-Y tion A to thewiper 5 merely tosimplify the i 1lustration,-thougl; ntcourse suchtelephone line could be extended the vmanner described as. in toll lineservice.- The talking wiper 5 has. an; wiper 6 that constitutes aterminal common to a l'urality of.

clintrollingfciruit's l; 8'an d 9. 1 conductor which is common tothesecontrolling cirmagnet 10, a batte v cuits', and fjwliichrcoiiductor thewiper 6 is ai' 'termin'ali includes. av wiper arresting llcommon to thecontrailing. circuits, an keys 12, 13 and 14, the --key'14'having anormal contact by which .Qtlie -k ey 13,.is 'connected with the battery11 *a'n'd the key '13 having a normal contact by which-theikjfim isconnected with such battery. The" alternatecontacts of keys 12, 13 an1'4 are respectively individual to the controlling circuits 7, 8 and 9.The controlling'circuit 7*pertains to the line extendingfroin-station'l, the controlling circuit 8-pertains-to "the lineextension from the station No. 2, and the controlling circuit 9 pertainsto the line extending from the stajele'ctro-magnets 15, 16 and 17individual to the lines 1, 2 and 3, these magnets being operatedwhen thelines to which they are ind-ividual are to become connected withteleph'one lines that are to be extended into connection therewith,these magnets serving to arrest the'connecting device 5, 6 inassociation with contacts 18 that pertain to desired telephone lineextensions and the controlling circuits associated therewith. Thecircuits 7 ,"8 and 9 include waiting contacts thatare individual theretoand which are designed to be engaged by the wiper 6. These waitingcontacts are provided each with an asso- 'c iate contact or set ofcontacts that are individual to the subscribers"telephone lines ortelephone line portions, such as trunk lines, that are to becomeconnected with the line which is to be extended. All of these *waitingcontacts are designated by the numeral 18 in Fig. 1. Assuming that acalling line (A) has in some way become connected with the wiper 5 andhas informed a receiving operator that he desires connecdepress the key12 so as to charge the waiting contact individual to the circuit 7. The

wiper rotating device 19. which has been set into operation by somesuitable means, is caused to turn the wipers until the wiper 6 engagesthe waiting contact individual to the controlling circuit 7 whereuponcircuit through the wiper arresting magnet 10 will be closed to arrestthe wiper 6 in engage- -l ine extensions 25 wit ment with its thenengaged waiting contact, in which engagement the wiper 5 is connected.with the line leading to station 1. Similarly, if station 2 is to beconnected with station A the key 13 will be depressed, whereupon wipers5 and 6 will become con nected with the middle group of contacts at 18,If station A is to be connected with station 3, the key-14 will bedepressed,

whereupon the wipers 5 and 6 will become connected with the third groupof waiting contacts at 18. The keys 12, 13 and 14 in addition tocharging the waiting contacts individual thereto also charge the wiper 6common to the controlling circuits with current of opposite. polarity sothat circuit is established when a charg d waiting contact is engaged bythe charge wiper. While the line to be extended is shown as beingprovided with traveling wipers and the line extensions are shown asbeing provided with waiting stationary contacts, I do not wish to be.limited to terminals for the line to be extended andcoiiperatingstationary terminals for the line extensions.

As is understood, the telephone line extension which is to be added toanother telephone line may be in the nature of trunk lines or linkconnectors, or may themselves be telephone lines that extend tosubscribers stations. In an exchange larger than that '20 is'providedwith traveling wipersindicated at 21, these wipers constituting a, lineextending connecting device for connection with one of the--lines ofthegroup to which it pertains. vThe sets of wipers 21- pertaining to thedifferent groups of subscribers telephone lines are to be selectedaccording to the group in which the desired line is included, thesewipers, being connected by means of telephone line extensions 22 withwaiting contacts illustrated at 23, each set of waiting contacts at 23beingv connected with a set of wipers 21. :Thewaiting con facts at 23are associated with wipers indicated'at 24, these latter wipers being;em-

ployedfor associatin one of the telephone I a selected telephone lineextension 22. There are aplural ty of sets of wipers 24 each inassociation with.

a difierent group of waiting contacts 23 and these wipers 24 areconnected through. the telephone line" extensions ,25. withwaiting'contacts illustrated at 26,:each set of waitin t s a 6 ei emm ted with aferent set of wipers 24. The waiting contacts 26 are associated withwipers indicated at 27, the wipers 27 being adapted to become connectedwith a selected one of several telephone line extensions 25 extending tothe desired set of'wipers 24. The wipers 27 are connected, for example,with calling station A by way of the cord and plug illustrated at 4,though other means may be employed for associating the wipers 27 withthe calling line. Thus by means of my invention the wipers 27 areconnected with one of several telephone line extensions 25 that has thewipers 24 that are associated with a particular set of waiting contacts23 that has the desired telephone line extension 22 which isprovidedwith wipers 21 that are associated with the waiting contacts 20 amongwhich are included those Waiting contacts that are terminals of thedesired'subscribers line. When a subscriber initiates a-connection inany suitable way 'and assuming that the system is presided over byoperators, the operator will proceed to extend the calling line intoconnection with the-desired line by the following operations: The key 28individual to the desired telephone line extension' and the associatecontrolling circuit (there being as many keys 28 and controllingcircuits to which they pertain as there are such telephone lineextensions 25 and each of which keys 28 may be multipled at differentoperators positions) is depressed partially to establish a circuitincluding the battery 11, the key 28 and its alternate contact, theclosed switch 29, a waiting contact at 26 which is in association withthe waiting contacts of the selected telephone line extension 25, thewiper 30, and the wiper arresting magnet 31. lVhen the wiper 30 engagesthe waiting contact connected with the switch 29, circuit is closedthrou h the magnet 31 to arrest the wipers where y the calling telephoneline is extended into connection with the desired telephone lineextension 25. By equipment to be described in connection with anotherfigure, the motor device 32 is set into operation when the selectedtelephone line extension 25 has been connected whereby switch 29 isopened to protect the circuit previously established at 28 so thatcontacts 26 of other switches which are similarly connected with otherkeys 28 and which contacts of these switches are inmultiple relationwith the contacts 26 shown, will not have their circuits partiallyestablished. The operator will depress the key 33 individual to thedesired telephone line extension 22 and the associate controllingcircuit (there being as many keys 33 and controlling circuits to whichthey-pertainas there are such telephone line extensions 22 and each ofwhich keys 33 may be multipled at different operators positions) topartially establish a circuit including the which is in association withthe batter 11,-the key 28 and its normal contact, t e key 33 and itsalternate contact, the closed. switch 34, a waiting contact a t 23walting contacts of the selected telephone line extension 22, the wiper35, and the wiper arv resting magnet 36. When the wiper 35 engages thewaiting contact connected with the switch 34 circuit is closed throughthe wiper 30, the contact engaged thereby, magnet 31 and the magnet 36to arrest these wipers whereby the calling telephone line is extendedinto connection with the desired telephone line extension 22. Byequipment to be described in connection with another figure, the motordevice 37 is set into operation when the selected telephone lineextension 22 has been'connect'ed whereby switch 34 is opened to protectthe circuit previously established at 33 so that contacts 23 of otherswitches which are similarly connected with other keys 33 and whichcontacts of these switches are in'multiple relation with the contacts 23shown, will not have their circuits partially established. The operatorwill also depress one of the keys 12, 13, 11 belonging to thecontrollingcircuit individual to the telephone line extending to the wantedstation, 1 2, or 3 (there being as many such keys and controllingcircuits to which they pertain as there are such telephone lines havingwaiting contacts at 20, that is there are as many keys 12, 13, 14 asthere are telephone lines in a group, and each of which keys 12, 13, 14may be multipled at different operators positions) partially toestablish a circuit including the battery 11, keys 28 and 33 and theirnormal contacts, the depressed key 12, 13 or 14 and its alternatecontact, the closed switch at 15, 16 or 17 according to'the lineselected, the waiting contacts at 20 which are in association with thedesired subscribers telephone line,

the wiper 38 and the wiper arresting maghet 39. When the wiper 38engages the waiting contact connected with the switch at 15, 16 or 17,circuit is closed through the magnet at 15, 16 or 17 (by way 'of wipers35 and 30 and magnets 36, 31) to arrest Wipers 38, 21

whereby the calling telephone line is ex-v tended into connection withthe desired subscribers line.

Fig. 3 is furnished to show more of the circuit connections that wereomitted from Fig. 2 for the sake of clearness. The system shown in Fig.3 illustrates how a calling line may secure access to each of the othernine hundred ninety-nine lines of a thousand line system, enoughapparatus being suggested in Fi 3 to accomplish this result. However t eequipment suggested in F ig. 3 is not sufiicient to take care of thetrafiic in a thousand line exchange and it is therefore understood' thatthe waiting contacts 26 of one switch are in mult ple rela i n withsimilar contacts 26 of other switches having wipers 27, 30 employed byother subscribers lines, there being say one hundred switches having thecontacts 26; that the waiting contacts 23 of each selector switch are inmultiple relation with similar waiting contacts of say two otherselector switches having' wipers 24. and that the waiting contacts 20 ofeach connector switch are in multiple relation with similar waitingcontacts of say nine other connector switches having switch having tensubscribers lines (1, 2,3,

etc.) terminating in the waiting contacts 20 and also having waitingcontacts that are in circuit with magnets 15, 16,17, etc. Where thereare three connector switches to each group of multiply connectedconnector switches ten subscribers lines are in connection with thewaiting contacts of each such switch. Each of the operators has a set often keys 28, the contacts of these keys 28 among the difi'erentoperators positions being multipled so that each operator may haveaccess to any of the switches having contacts 20 and to said contacts26. Each of the operators has a set of ten keys 33, the contacts ofthese keys 33 among difierent operators positions being multipled sothat each operator may have access to any of the switches havingcontacts 23 and to said contacts 23. Each of the operators has a set often keys 12, 13, 14, etc., the contacts of these keys 12, 13, 14, amongdifferent operators positions being multipled so that each operator mayhave access to any of the switches having contacts 20 and to saidcontacts 20. Where the exchange exceeds 1.000 lines, additionalconnector switches will be required and it will be readily understood bythose skilled in the art how an exchange in excess of 1,000 lines maybeequipped by the interposition of other selector switchesin advance ofthe connector switches, such at dit'ional select'c r switches of courserequiring associate buttons having functions similar to the buttons 33.The thousand. line sys tem which has been taken for an exani'pie willbe. suflicient to enable my invention to'he understood.

Reference will now be, hadto Figs. 1 and which amplify the timearrangement shown in Fig. Assuming that subscribers station U0. 1desires communication with subscribers station No. 2, the callingsubscriber will rembve his telephone re'ceiver 40'from its switch hook41 to open the bridge containing the signal bell 42 and condenser 43 andto close the metalic'ally continuous bridge containing the telephonetransmitter 44 and the telephone receiver 40. Circuit is thereuponestablished through the relay 45 which may be traced from the groundedterminal of this relay through its winding, the upper armature switch ofringing relay 46 and its normal contact (this relay being operated onlywhen its line is :1 called line), the sides of the calling line, thelower armature switch of relay 46, and its normal contact, next to theuppermost armature switch of relay l5 and its contact, the relay 47 tothe grounded battery 48, the battery 48 also supplying, talking currentto the transmitters. The relay 47 may be common to the lines of a groupof subscribers lines and when its armature is attracted acircuit isestablished which is traceable from the grounded battery 48 through thecircuit interrupter 49, the armature of relay 47 and its contact, thelowermost armature switch of relay 50 and its normal contact, themotormagnet 51, to ground. .The circuit of the motor magnet 51 is interruptedso that its armature moves the ratchet wheel 52 that carries wipers 53,54, 55, 56 and 57 that pass over sets of waiting contacts belonging tothe group of telephone lines having the relay 4?, there being two setsof such'waiting contacts indicated at 58, 59, 60, 01 and (S2. \Vhen asubscriber initiates a call a circuit connection is established for thewaiting contact 62 belonging to his line which circuit connection may betraced from the contact 62 of the calling line, the lowermost armatureswitch of relay 45 and its then engaged contact, the follow-up contactof the armature switch immediately above the core of relay 15, the upperwinding of the relay- 15, to the grounded battery 48. That is potentialis laced upon the waiting contact 62 of a callmg line by connecting thegrounded battery 48 therewith, the contacts 62 of non- Calling'linesbeing clear of such potential. When the wiper 57 engages thecontact 62 having this potential the circuit-connection just traced hasa continuation that establ,ishes a closed circuit which continuationincludes the, wiper 57, the follow-up normal Contact of the upperarmature switch of -relay 50, the windin of relay 50, the upper armatureswitch 0 relay 63 and one of its contacts, to ground. Thus the magnet 50becomes energized and its upper armature switch leaves its normalfollow-up contact into engagement with its alternate contact core ofthis relay having left its normal follow-up contact and now engaging itsalternate'contact to the circuit initially es-- tablished for this relay15 at the-lowermost armature switch of the previously energized relay-15), the armature switch imn'iedi'ately above the core of relay 15, thealternate contact of this arn'iature switch, the waiting contact 59 ofthe operated wipers, the wiper 5i engaging this waiting contact, theupper armature switch of relay 50 and its alternate contact, the windingof this relay 50, the upper armature switch of relay 63 and one of itsnormal contacts, to

ground. The locking circuit for the upper winding of relay 15 continuesthrough its armature switch immediately above its core, the alternatecontact of this armature switch, both sides of the calling subscriber'sline, the relay 45, to ground.

One ide oi each telephone line is permanently connected with the talkingwait ing contact 539 and the other side of each si'ibscribers line isconnected with the talking waiting contact 58' when the upper armatureswitch of relay 45 is attracted. Thus the talking waiting contacts 58and are connectedwith the talking wipers and 54- respectively, wherebythe operators telephone conductors 64 are connected with the callingsubscribers line to include the operators telephone set 65 in circuitwith the calling subscribers line. The operator is now in telephoniccommunication with the calling subscriber, this feature of the inventionbeing covered by my application Serial No. 503,345, filed June 21, 1909,though it is to be understood that in practising my invention I- do notlimit myself to the manner in which communication is established between'calling subscribers and the operators. lVhen the operator has receivedthe number of the desired line she actuates the buttons orswitches thatpertain to the waiting contacts of the desired line, the waitingcontacts extending to the wipers 21, 38 of the connector switch of thedesired line, the waiting contacts pertaining to the selected telephoneextension 22, and the waiting contacts pertaining to the selectedtelephone extension 25, these: buttons being illustrated at the right ofFig. and thereafter depresses the button or switch (36.

Two sets of such buttons are shown and two operators telephone sets (35are shown, these elements being located at two operators positions. Whenthe selected buttons 28, 33, 12, 13 or l l are initially depressed theyare not then immediately effective, the circuits controlled by thesebuttons being open at the lowermost armature switch of relay 63. Thebutton 66 has a plunger in which there is a notch 67, this notch beingnormally out of line with the nose of the armature of re lay 68. Whenthe button 66 is depressed its notch 67 is brought into register withthe nose of the armature of relay 68 so that this armaturethen engages agrounded contact to establish a circuit which is traceable from thisgrounded contact through the armature of magnet 68, and the winding ofmagnet 50 whereby a ground for magnet 50 replaces the ground previouslyprovided for this magnet at the upper arma ture switch of relay 63 andwhich latter ground is later removed when the ma gnet 63 is energized.pressed it moves .the switch. members (39 and 70 into engagement withtheir contacts.

the switch 70 closin a circuit which may be traced from the groundedarmature switch of relay 63, the contact connected with the switchmember 70, the contact engaged by the s vitch member 70, the actuatedwiper 56, th waiting contact 61 engaging this wiper, the lowermostarmature switch of relay ]5 and its previously engaged contact, thelowermost armature switch of re; lay 71 and its normal contact, themotor magnet .62, the interrupter 49, to the grounded battery 48. Themotor magnet 62 due to the interrupter. 49 operates the ratchet wheel 72to cause the wipers 74, 75 carried by the ratchet wheel to travel untilthese wipers engage wa ting contacts 76, 77, 78 that are free forengagement, such contacts being free for engagement' when the contacts78 thereof are 0011-, nected with the ground at the relay 63, therebeing one such relay for each operators position and such connectionbeing cffected when a calling subscriber is connected with an operatorin a manner previously described. The grounded battery 48 is connectedwith the wiper 75 by way of the switch 79 which is closed upon theinitial movement of the ratchet wheel 72, the wind ing of relay 71, theupper armature switch of this relay, and the normal follow-up contact ofthis armature switch so that when the wiper 75 engages the contact 78the magnet 71 is energized to establish a lockingcircuit for itselfwhich continues through its upper armature switch and its alternatecontact, the actuated wiper 74,. the contact 77 engaged thereby, oneside of the calling line, thecalling substayion, the other side of thecalling line, to tie ground at hen the key 66 is dethe relay 45. Whenbatterywas connected with the ,wiper through the normal follow-upcontact of the upper armature switch of relay '71, current from batteryfound passage from the wiper 7 5 through the contact 78, the employedwaiting contact 60, the actuated wiper 55, the intermediate armatureswitch of relay 63 and its normal follow-up contact, the winding ofrelay 63, to ground. The relay 63 is now energized and establishes alocking circuit for itself which is traceable from the grounded coil ofrelay 63, the alternate contact of its intermediate armature switch, theswitch element 69 and its contact, to the grounded battery 48. removedfrom the employed contact 78 so that the wipers 73, 7 k, 75 of any otherswitch cannot rest upon any waiting contacts in multiple with thecontacts 76, 77, 78 of which contact 78 is grounded, it bein understoodthat the waiting contacts 76, 77, 78 have multipled counterparts inswitches having wipers similar to 73, 74 and 75. The removal of groundconsequent upon the attraction of the upper armature switch of relay 63has opened the circuit of the motor magnet 62 so that this motor magnetceases to work and allows its wipers to remain in engagement with theautomatically selected waiting contacts. Only two switches having thewipers 73, etc., are shown and. the lowermost switch is caused to.operate first if the other switch is idle owing to the fact that themotor magnet 62 of the upper switch depends partially for its circuitupon the engage-- ment of the lowermost armature switch of the lowerrelay 71 with its alternate contact. If there were more switches withmotor magnets 62 the switches would be permitted to operate insuccession by means of the lowermost armature switches of relays 71introduced therebetween. The talking wipers 73 and 74- and theadditional wiper 75 are respectively connected with the-two talkingwipers 27 and the extra wiper 30, which latter wipers are now broughtinto connection with the waiting contacts 26 as a consequence of theestablishment of a circuit which may be tracedfrom the grounded battery48, the interrupter 49, the motor magnet 79, the lowermost armatureswitch of relay 31-and its then engaged contact, the waiting contact v76engaged thereby, to the grounded relay 45 by Way of its upper armatureswitch. The armature of magnet 79 operates a ratchet wheel 80 thatcarries wipers 27, 30 and this ratchet wheel continues to rotate untilthe rotating wiper 3O enga es a waiting contact at 26 'complemental tereto and which complemental waiting contact at 26' has battery placedthereupon by a path traceable from the lower pole of the-bat? to thewiper-30. Circuit is closed when the Ground is now terminates in talkingwipers 24: and an ex:

removing the bell crank lever from this tery 11, the winding-of tripmagnet; comniou'to'button's 28 at' an ope'ratorfs'jposition, theserially related switches that" iii-- clude the bell "crank contactlcvers i82 p'iy oted'at'their lower ends 'to"the-'pa'rticu lar 70 Switch28, in this inst'ance'j'the uppermost switch,- the contacts 8 3 of, thedepressed switch 28, the switch '29 and its normal; contact, to thewaiting conta'ct26 co nplementali 75 employed wipergw 'engages thecontact 26 thus connectecl with battery 11 owingto the fact that thewiper 30 is connectediwith the upper terminal of tlie battery 11 byapath.

.minal jof't hisbattery, the lowermost actu-i ated; armature switch ofrelay 63 and its"-- contact, theactuated wiper 55, the waiting contact'60 engaging the same, the employed waiting contact 78 and the actuatedwiper 85 75 engaging'the same, the switch 8 4 closed upon the initialoperation of the ratchet 80, the upper windin' relay 31, to theaforesaid wiper The up er coil of re-' lay 31 thus becomes energized toa'rrest the' wipers by opening the circuit of the motor magnet 7-9 atthe lowermost armature switch of relay 31. The relay 31 is providedwith; a lower winding that serves to maintain the energization of therelay core, the cir'-'95 cuit bein traced from the grounded batter'y 48,t e lower'windin of relay 31, the." upper armature switch'o relay 31 andits previously engaged contact, the actuated wiper 74% and the waitingcontact 77 era-.1 gaged thereby, both sides of the calling line,

to the grounded relay 45. 'The 'talking wipers 27 are now connected witha'selected line extension 25. This line extension 25 tra wiper 35, suchline extension being prevented from selection by any other wipers 27, 3Oowing to the fact that batteryllf. is disconnected from the waitingcontact 26 engaged by the arrested wiper 30 at the previously engagedcontacts 83 which are separated by the circuit established through-- therestoring magnet 81 and the battery 11, the bell crank element 82 of theactuated key having previously entered a normally unalined notch 86whenthis notch is'bro'ught into alinement with the upper branch of the bellcrank lever upon the depression of the key having the notch, the magnet'81.

notch'when this magnet is energized so as to restore. the key and permitthe contacts 83 to separate. The armature of the magnet j v 81 is shownas being common to the keys; 28 for this purpose. The selection ,pf abus line extension 25 is furtherjgiia' v 1? against by the separationofthe'swit'chw from its normal contact upon 'the initial operation ofthe motor magnet 87. (in

cuit forthe motormagnetfif is traceable 130 from the grounded battery48, the interrupter 49, the winding of said motor magthe wiper 73, thewaiting contact-76, to the grounded relay (by way of its upper armatureswitch) of the calling line. lhe connection of the wipers 24 and withthe selected waiting contacts 23 is had by operations similar to thoseemployed for connecting wipers 27, 30 with the waiting contacts 26 andthe magnet 36 operates similarly to magnet 31 for arresting thesewipers. The buttons 33 have an associa tion with the ratchet 37 andassociating mechanism similar to the association of buttons 28 with themechanism of ratchet 32 and the wipers 21, 38are brought into engagementwith selected wipers 20 in a manner similar to that employed forconnecting the wipers 27 30 with the contacts 26. The structuralmechanism of the keys- 28, 33, 12, 13. 14 are similar and similar partsof these keys are given similar characters of reference.

I will now describe the results of the operation of the final key, inthis instance key No. 13, as line No. 2 isthe called line. From Fig. 5it will be seen that all the keys employed in extending a telephone linemay be depressed simultaneously but that a depressed key 33 cannot comeinto service until the operations set up by the depressed key 28 haveoccurred and a depressed key 12, 13, etc., cannot come intoserviceiuntil the operations set up by the depressed key 33 haveoccurred. It will also be observed that .7- the keys are automaticallysuccessively brought into effect, each succeeding key as it is broughtinto effect being preceded by the restoration of the preceding key. Whenthe depressed key 13 is automatically reached to enable it to take partin the line extending operation the circuit previously partiallyestablished at 83 is completed, this of relay 31 and its now engagedcontact, the.

actuated wiper 30 and ,the contact 26 engaging the same, the switch 29and its alternatev contact, the intermediate armature switch of relay 36and its engaged contact, the

and its engaged contact, the wiper 38 and the contact 20 engagedthereby, the arznature switch of relay 16 immediately beneath the coreof this relay and the normal follow-up contact of this armature switch,the lower winding of relay 16, the previously closed contact 83 of thekey 13, the employed magnet 81, the relay 68, the series of switches 82of keys 33, all of which are now in normal position, the magnet 81pertaining to the keys 33, the seriesof switches 82 of keys 28, themagnet 81 pertaining to the keys 28, to the lower pole of the battery11. The relay 16 belonging to the called line is now energized, and alocking circuit for itself is established traceable from the groundedbattery 48, theupper winding of relay 16, the armature immediately abovethe core of relay 16 and its alternate contact, the lower of the twowipers 21 and the waiting contact 20 engaged thereby, the lower of thetwo wipers 24- and the waiting contact 23 engaged thereby, the lowermostof 85 the two wipers 27 and the waiting contact 26 engaged thereby, thewiper 74 and the contact 77 engaged thereby, both sides of the callingsubscribers line, the calling subscribers relay 45, to ground. A circuitwas previously traced through the relay 68 and this circuit caused thisrelay to be energized to withdraw its armature and thereby remove groundat this armature from the magnet '50 of the operator selector switchwhich was actuated-as a consequence of the mature of relay 68 wasattracted its nose was disengaged from the notch 67 of the pre- 10.;viously depressed key 66 so that the key 66 was automatically restoredto normal and I in being so restored the switchlevers 69 and 70 wereseparated from their contacts. The associate magnet 63 then has itscircuit open .at 69 and this magnet 63 is restored to normal and groundconnection with the wiper 55 is broken at 70 so that the previouslyemployed operator selector switch may again be employed when anothercall is initiated. 11;; Thus the operator is freed for further selectionand the apparatus of keys 28, 33,

12; etc., are restored to normal. The ringing magnet 46 of the calledline is consequently energized over a circuit. tracealiilc 126 from thegrounded battery 48 through the ringing interrupter 88, the uppermostarmature switch of the called subscribers relay 16, and its then engagedcontact, the middle switch of called subscribers relay 45 and itscontact, the winding of the called subscribers ringin relay 46, toground. This ringing relay 1s consequently intermittently energizedintermittently to include 'theringing generator 89 in bridge of the 130called line by way of the armature switches of the ringing relay 46 andthe alternate contact of these armature switches that constituteterminals of said generator. When the called subscriber responds thegenerator 89 is automatically cut out of circuit during one of theperiods in which the actuated ringing relay 46 is denergized and inwhich period the called subscribers telephone is removed from its hookwhereby the called subscribers relay 45 is then energized to open thecircuit of the ringing relay 46 to maintain this ringing relaypermanently in open circuit duringthe established'connection. Thecircuit of relay 45 of the called line is traceable from the groundedterminal of this relay 45, both sidesof the calling line by way of thereleased armature switches of ringing relay 46 and their normalcontacts, the armature switchof called subscribers relay 16 immediatelyabove the core of this relay and the alternate contact of'this armatureswitch, the upper coil of this relay 16, to the'grounded battery 48, thecircuit for the ringing relay 46 being kept open at the middle armatureswitch of the now energized relay 45. The attracted upper armatureswitch of relay 45 extends the called line into connection with the con-(luctors leading to the waiting contacts 20 engaged by the Wipers 21 sothat connection between the calling and called lines is now completed.WVhen the parties are through conversation their relays 45 aredenergized on the restoration of the telephone receivers upon theirswitch hooks whereby the relays 15, 16, 39, 36, 31' and 71 are includedin open circuit so that the armatures of these relays are restored tonormal. When the armatures of relays 39, 36, 31 and 71 are restored tonormal they disengage the actuating pawls' ofthe associate motor magnetsfrom the ratchet Wheels previously operated by these pawls so that theseratchet wheels are restored to normal, as shown in Fig. 6.

Any suitable test feature may be employed. As the system is employedfailure of the depressed buttons 12, 13, etc., to restore the normalwill indicate to the operator that the desired line is busy and inasmuchas the operator is not released until this button is restored theoperator may'inform the calling subscriber that the desired line isbusy. a

Fig. 6 indicates a. delaying device by which the ratchet wheel ispermitted to re store to normal prior to the return of the actuatingpawl of the motor magnet to the position in which it may actuate theratchet wheel. The delaying detent a is pivoted at b and is pulled uponby a spring 0 so as to have a position to engage the pawl d of the motormagnet when this pawl is raised by the finger e operated by the holdingmagnet when energized. When the holding magnet" 'is denergized thefinger f fixed upon the ratchet wheel strikes the holding pawl a, whenthe ratchet wheel has reached normal, and releases the holding pawl fromengagement with the actuated pawl operated by the motor magnet so thatthis actuated pawl may be restored to its relationship with the ratchetwheel.

In my co-pending application Serial No.

714,417, filed August 10, 1912, I have claimed the key mechanism 28, 33,12, 13, etc, and I do not limit my present invention to the employmentof this key mechanism. -It is desired to make cross reference to myfollowing copending applications: Serial No. 709,405, filed July 15,1912, Serial No. 709,406, filed July 15, 1912, and Serial No. 709,407,filed July 15, 1912, in which are broadly claimed operator controlledelectromagnetic switches for establishing connection between callinglines and calling line extensions or other telephone lines. By means ofone of the systems disclosed in these co-pending applications callingline terminals are moved into connection with contacts of linkconnectors; in another sys tem direct connection is effected betweencontacts belonging to calling lines and contacts belonging to calledlines; and in the remaining system contacts belonging to link connectorsare moved into connection with contacts belonging to the calling lines.

While I have herein shown and particularly described the preferredembodiment of my invention, I do not wish to be limited to the precisedetails of construction and circuit arrangement shown as change mayreadily be made without departing from the spirit of my invention.

' Having thus described my invention I claim as new and desire to secureby Letters Patent the following I 1. A telephone system includingtelephone lines extending from stations to an exchange; extensions forsuch telephone lines having contacts at the exchange; a line extendingconnecting device for engagement with the contacts; controlling circuitsfor governing the association of said connecting device, eachcontrolling circuit having a contact for engagement with the connectingdevice, the controlling circuits being associated with difierenttelephone line extensions; means for changing the character of thecontrolling circuits; electro-magnetic mechanism in the controllingcircuits for maintaining the connecting device in association with amodified controlling circuit; and electro-magnetic switches individualto the controlling circuits for restoring such circuits when theirassociate line extensions have become connected with telephone lines:

2. A telephone system including telephone lines extendin from stationsto an exchange; extensions for such telephone lines -means individual tothe controlling circuits for restoring such circuits when theirassociate line extensions have become connected with telephone lines.

3. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange;a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting de- 1 vice the controlling circuits'beingassociated with different telephone line extensions; means for changingthe character of the controlling circuits; elec'tro-magnetic mechanismin the controlling circuits for maintaining the connecting device inassociation with a modified controlling circuit; and electromagneticswitching mechanism for restoring such circuits when their associateline extensions have become connected with telephone lines.

fl. A telephone'system including telephone lines extending from stationsto an exchange: extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for gi' verning the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device the controlling circuits beingassociated with different telephone line extensions; means for changingthe character of the controlling circuits; electro magnetic -mecha nismin the controlling circuits for maintaining the connecting device inassociation with a modified controlling circuit; and means for restoringsuch circuits when their associate line extensions have become connectedwith telephone lines.

5. A telephone system including telephone lines extending from stationsto an exchange: extensions for such telephone lines having contacts atthe exchange; a line .ex-

tending connecting device for engagement with the contacts; controllingc1rcu1ts for governing the association of said connecting device, eachcontrolling circuit having conmet o e g g ent with the connectingdevice, the controlling circuits being associated\ with differenttelephone line extensions; Qmeans indivldual to the controlling circuitsfor changing the character of the controlling circuits; electro-magneticmechanlsm 1n the controlling circuits for maintainingthe connectingdevice in association with a modified controlling circuit; and means forrestoring such circuits when their associate line extensions have becomeconnected with telephone lines.

(3. A telephone system including telephone lines extending from stationsto an exchange; extensions forsuch telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with difierent telephone line extensions; means for changingthe character of the con trolling circuits; and electromagneticmechanism in the controlling circuits for maintaining the connectingdevice in association with a modified controlling circuit.

7. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line ex tendin connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a con tact forengagement with the connecting dewith different telephone lineextensions;

'means, for changing the character of the controlling clrcults; meansfor main-taming the connecting device in association with a moditiedcontrolling circuit; and electromagnetic switches individual to thecontrolling circuits for restoring such circuits when their associateline extensions have become connected with telephone lines.

8. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement withvthe connecting derice. the controlling circuits beingassociated with difi'crent telephone line extensions; means for changingthe character of the controlling circuits; means for maintaining theconnecting device in association with a modified control-ling circuit;and means individual to the controlling circuits for r.estoringsuchcircuits when their associate line extensions have become connected withteleph ne lines.

9. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting de-- 'vice, the controlling circuitsbemgassociated with the contacts; controlling circuits for governing theassociation of said connecting.

device, each controlling circuit having a contact for engagement withthe connecting device, the controlling circuits being associated withdifferent telephone line extensions; means for changing the character ofthe controlling circifits; means for maintaining the connecting devicein association with a modified controlling circuit; and means forrestoring such circuits when their associate line extensions have becomeconnected with telephone lines.

11. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a con tact forengagement with the connecting device, the controlling circuits beingassociated with diflerent telephone line extensions; means individual tothe controlling circuits for changing thechara-cter of the controllingcircuits; means for maintaining the connecting device in associationwith a modified controlling circuit; and means for restoring suchcircuits when their associate line extensions have become connected withtelephone lines.

12. A telephone system including telephone linc extending from stationsto an exchange: extensims for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device in determining the extensions of telephone lines, eachcontrolllng circuit having a contact for engagement with the connectingdevice, the controlling circuits being associated with differenttelephone line extensions; means for changing the.,character of thecontrolling circuits; means for maintaining the connecting device inassociation with a modified controlling circuit; and means for restoringsuch circuits when their associate line extensions have become connectedwith telephone lines.

18. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a

line extending connecting device for en.

gagement with the contacts; controlling circuits for governing theassociation of said connecting device, each controlling circuit havingacontact for engagement with the connecting device, the controllingcircuits being associated with difierent telephone line extensions;operator controlled means for changing the character of the controllingcircuits; electro-magnetic mechanism in the controlling circuits for.maintaining the connecting device in association with a modifiedcontrolling circuit; and electromagnetic switches individual to thecontrolling circuit s for restoring such circuits when their associateline extensions have become connected with telephone lines.

14:. A telephone system including telephone lines extending fromstations to an exchange; extensions for such telephone lines havingcontacts at the exchange; a line extending connecting device forengagement with the contacts; controlling circuits for governing theassociation of said connecting device, each controlling circuit having acontact for engagement with the connecting device, the controllingcircuits being associated .with different telephone line extensions;operator controlled means for changing the character of the controllingcircuits; electro-magnetic mechanism in the' controlling circuits formaintaining the connecting device in association with a modifiedcontrolling circuit; and means individual to the cpntrolling circuitsfor re storing such circuits when their associate line extensions havebecome connected with telephone lines.

15. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with different telephone line extensions; operator controlledmeans for changing the character of the controlling circuits;electro-magnetic mechanism in the controlling circuits for maintainingthe connecting device in association with a modified controllingcircuit; and electromagnetic switching mechanism for restor ing suchcircuits when their associate line extensions have become connected Withtelephone lines.

16. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with ditferent telephone line extensions; operator controlledmeans for changing the character of the control ling circuits;electro-magnetic mechanism in the.controlling circuits for maintainingthe connecting device in association with a modified controllingcircuit; and means for restoring such circuits when their associate lineextensions have become connected with telephone lines.

11A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association otsaidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits heingassociated with different telephone line extensions; operator controlledmeans individual to the controlling circuits for changing the characterof the controlling circuits; elcctro-magnetic mechanism in thecoi'itrolling circuits for maintaining the connecting device inassociation with a modified controlling circuit; and means for restoringsuch circuits when their associate line extensions have become connectedwith telephone lines.

18. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device the controlling circuits beingassociated with different telephone line extensions; operator controlledmeans for changing the character of the controlling circuits; andelectromagnetic mechanism in the controlling circuits for maintainingthe connecting device in association with a modified controllingcircuit.

19. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts controlling circuits for governing the association of saidconnecting phone lines extending from stations to an exchange;extensions for such telephone lines having contacts at the exchange; aline extending connecting device for engagement with the contacts;controlling circuits ffor governing the association of said connectingdevice, each controlling circuit having a contact for engagement withthe connecting device, the controlling circuits being associated. withdifferent telephone line extensions; operator controlled means forchanging the character of the controlling circuits; means formaintaining the connecting device in association with a modifiedcontrolling circuit; and means individual to the controlling circuitsfor restoring such circuits when their associate line extensions havebecome connected with telephone lines.

21. A telephone system including tclephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device. each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with different telephone line extensions; operator controlledmeans for cl'ianging-the character of the controlling circuits; meansfor maintaining the connect ing device in association with a modifiedcontrolling circuit; and electro-magnetic switching mechanism forrestoring such circuits when their associate line extensions have becomeconnected with telephone lines.

22. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with diiierent telephone line extensions; operator controlledmeans for changing the chanactcr of the controlling circuits; means formaintaining the con necting device in association with a modifiedcontrolling circuit; and means for restoring such circuits when theirassociate line extensions have become connected with telephone lines.

23. A telephone system including telephone lines extending from stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement with thecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with theconnecting device, the controlling circuits beingassociated with different telephone line extensions; operator controlledmeans individual to the controlling circuits for changing the characterof the controlling circuit-s;

means for maintaining the connecting device in association with amodified controlling circuit; and means-for restoring such circuits whentheir associate line extensions have become connected with telephonelines.

24. A telephone system including telephone lines extending from-stationsto an exchange; extensions for such telephone lines having contacts atthe exchange; a line extending connecting device for engagement withthecontacts; controlling circuits for governing the association of saidconnecting device, each controlling circuit having a contact forengagement with the connecting device, the controlling circuits beingassociated with different telephone line extensions; operator controlledmeans for changing the character of the controlling circuits; and meansfor maintaining the connecting device in association with a modifiedcontrolling circuit.

A telephone system including telephone lines; extensions for suchtelephone lines; a line extending connecting device for associating aselected telephone line extension with the telephone line having theconnecting device; controlling circuits associated with differenttelephone line ex ten sions for governing the association of saidconnecting device in determining the extensions of telephone lines;means for changing the character of the controlling circuits; and

means for restoring. such circuits when their associate lineextensionshave become connected with telephone lines.

26. A telephone system including telephone lines extending to anexchange: extensions for such telephone lines; a line ex tendingconnecting'device; controlling cir' ocales cuits associated withdifi'erent telephone line extensions for governing the association ofsaid connecting device; and operator controlled means tor changing thecharacter of the controlling circuits.

27. A telephone system including telephone lines; extensions for suchtelephone lines; a'line extending connecting device; controllingcircuits associated with different telephone line extensions forgoverning the association of said connecting device; and operatorcontrolled means for changing the character of the controlling circuits.

28. A teiephonesystem including tele phone lines; extensions for 'suchtelephone lines; a line extending connecting device; controllingcircuits associated with different telephone line extensions forgoverning the association of said connecting'device in determining'theextensions of telephone lines; means for changing the character of thecontrolling circuits; means governed by the controlling circuits, whenmodified, for maintaining the extensions associated therewith inconnection with the line extending connecting device; and means. forrestoring such circuits when their associate lineextensions have becomeconnected" with telephone lines. 7

29. A telephone system including telephone lines extelnding to anexchange; extensions for such telephone lines; a line extendingconnecting device; controlling cireuits associated with difl'erenttelephone line extensions for governing the association of saidconnecting device; operator controlled means for changing the characterof the controlling circuits; and means governed by the controllingcircuits, when modified, for maintaining the extensions associatedtherewith in connection with the line extending connecting device.

30. A telephone system including telephone lines; extensions for suchtelephone lines; a line extending connecting device; controllingcircuits associated with diflerent telephone line extensions forgoverning the association of said connecting device; operator controlledmeans for changing the char actor of the controlling circuits; and meansgoverned by the controlling circuits, when modified, for maintaining theextensions associated therewith in connection with the line extendingconnecting device.

BLL'A telephone system including tele phone lines; extensions forsuchtelephone lines: a line extending connecting device; controllingcircuits associated with different telephone line extensions forgoverning the association of said connecting device in determining theextensions of telephone lines and individual to the line extensionspertaining to the line extending connecting device: means for changingthe eharacterof the controlling circuits; and means 50! re storing suchcircuits when their associate line extensions have become connected withtelephone lines,

32. A telephone system including telephone lines extending to anexchange; ex-

. tensions for such telephone lines; a line ter of the controllingcircuits.

A telephone system including telephone lines; extensions for suchtelephone lines; a line extending connecting device; controllingcircuits associated with different telephone line extensions forgoverning the association of said connecting device and individual tothe line extensions pertaining to the line extending connecting device;and operator controlled means for changing the character of thecontrolling'circuits.

34. A. telephone system including telephone lines; extensions for suchtelephone lines; a line extending connecting device; controllingcircuits associated with different telephone line extensions forgoverning the association of said connecting device in determining theextensions of telephone lines and individual to the line extensionsperraining to the line extending connecting detl'ce; means for changingthe character of the controlling circuits; means governed by thecontrolling circuits, when modified for maintaining the extensionsassociated therewith in connection with the line extending connectingdevice; and means for restoring such circuits when their associate lineextensions have become connected with telephone'lines. i I

35; A telephone system including telephone lines extending to anexchange; extensions for such telephone lines; a line extendingconnectin device; controlling circuits associated wlth differenttelephone line extensions for governing the association of saidconnecting device and individual to the line extensions pertaining -tothe line extending connecting device; operator controlled means forchanging the character of the controlling circuits; and.

means governed by the controlling circuits, when modified formaintaining the extensions associated therewith in connection with theline extending connecting device.

36. A telephone system including tele phone lines; extensions for suchtelephone line.-.1 a line extending connecting device;

taining to the line extending connecting device; operator controlledmeans for changmg the character of the controlling cir cuits; and meansgoverned by the controlling circuits, when modified, for maintaining theextensions associated therewith in connection with the line extendingconnecting device.

'37. A telephone exchange system including telephone lines extendingfrom stations to an exchange; extensions for such telephone lines; anelectromagnetic line extending switch having a number of sets of waitingcontacts pertaining to different telephone line extensions, and a set ofWipers for interchangeable connection with said sets of waitingcontacts; electro-magnetic mechanism for holding the wipers inconnection with the waiting contacts; and operator governed controllingcircuits pertaining to the different telephone line extensions forcontrolling said electro-magnetic mechanism and having waiting contactsin the sets of waiting contacts to enable the operator to determine theset of waiting contacts to be engaged by the set of Wipers.

38. A telephone system including telephone lines; extensions for suchtelephone lines; an electro-magnetic line extending connecting device;switching mechanism for setting said connecting device into operation:and manually modified controlling circuits individual to the difierenttelephone line extensions and each serving, when modified, to stop themoving connecting device in connection with the corresponding telephoneline extension.

39. A telephone system including telephone lines; extensions for suchtelephone lines; an electro-magnetic line extending connecting device;switching mechanism for setting said connecting device into operation;and controlling circuits having opera. tors means for modifying the sameand which are individual to the different telephone line extensions andeach serving, when modified, to stop the moving connecting device inconnection with the corresponding telephone line extension.

In witness whereof, I hereunto subscribe my name this sixth day ofAugust A. D., 115

ILMER R. CORVVIN. \Vitnesses G. L. CRAGG, E. L. WHITE.

Copiers this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, 3.3.0.

